We present design, analysis and characterization of dual-mode vertical comb-drive actuated micromirrors. The micromirrors are actuated by vertical comb drive actuators that enable large deflections at relatively low voltages with continuous stable control over the full range of motion. The electrode layout of the dual-mode actuators allows us to independently control the piston motion and tilt of the micromirrors. This enables precise control of the phase of optical beams reflected from arrays of micromirrors. Our experimental results show that dual-mode actuation significantly increases the angular range of motion of the mirrors, and we demonstrate phase-front control by spatially scanning an optical beam using a phasedarray consisting of four dual-modemicromirrors.